High Obliquity Impact of Soft and Hard Spheres on Thin Plates

This paper presents a combined experimental-computational study of the impact of steel spheres on thin armor plates at an oblique angle of 70 deg. The plates were nominally 6 mm thick, rolled homogeneous armor. Two types of spheres were used, a hard steel and a soft iron. In all cases the velocity was around 1500 m/s. This combination of velocity and materials resulted in plate perforation for the hard spheres, whereas for the soft spheres the plates were not perforated. The impact process was radiographed at 5µs intervals and the plates were cut to allow an examination of their cross-section. The simulations were carried out with two hydrocodes: the DYTRAN code, employing an Euler solver, and the AUTODYN code, using an eroding Lagrange solver. The results of the simulation agree quite well with the experimental material contours obtained from radiographs, and with the final crater shapes.